1. Field of the Invention
This invention relates generally to teaching machines and, more particularly, to teaching machines of the type in which the answer to a problem on an inserted record member appears on a display only if the student first enters the correct answer into the machine.
2. Description of the Prior Art
A number of teaching machines have been disclosed in which the student enters an answer to a displayed problem and the machine confirms the answer if it is correct. These machines have generally not achieved wide acceptance as standard teaching aids for the everyday teaching of subjects to classes of students, since all of them have severe disadvantages which prevent them from being practicable.
One such teaching machine, which is described in U.S. Pat. No. 3,172,216, makes use of a program disc whose surface is divided into a number of concentric zones. The statement of a mathematical problem is recorded adjacent to the problem in the next zone toward the center. The next inner zone of the disc is an answer area in which are punched coded answer holes. When a student enters a correct or an incorrect answer or takes too much time in deciding on an answer, a corresponding stylus is activated and produces a mark on a central zone of the disc.
The statement of a problem on the disc is visible to the student through a viewing port in the machine and a keyboard is provided for allowing the student to enter an answer. If the entered answer is correct, a series of indicator lights are illuminated. Once the student has entered an answer, he may expose the correct answer recorded in the disc by operating an answer check key.
This teaching machine has several disadvantages. It is complex and bulky and much too expensive to permit a school to have one available for each member of a class. Furthermore, it is not practical for use in testing a student's mathematical knowledge, since in order for the instructor to determine the number of correct and incorrect answers, he must count the number of marks on the central protion of the disc. If it is necessary to do this for any appreciable number of students the task becomes too burdensome to be carried out on a regular basis. Furthermore, the use of styli in the machine present substantial reliability and maintenance problems which would prevent this machine from being practical for general classroom use.
Another teaching machine, described in U.S. Pat. No. 3,584,398, randomly generates problems electroncially to be solved by the student. This machine is also clearly not suitable for general class use since there is no way of controlling the difficulty level of the problems being presented to the student. Thus in any given period of time the problems presented by the machine to one student may be more or less difficult than those presented to another student, thereby preventing any meaningful determination of relative progress.
U.S. Pat. Nos. 2,564,089; 3,212,199; 3,521,381; and 3,553,853, all disclose teaching machines which are much too complex, bulky and expensive for general classroom use.
U.S. Pat. Nos. 3,070,904; 3,508,349 and 3,696,526, on the other hand, disclose educational devices of such an elementary nature little more than games.